One example of a type of image forming apparatus that forms images on recording media is an image forming apparatus that adopts an inkjet method (referred to below as an “inkjet recording apparatus”). The inkjet recording apparatus for example includes a plurality of recording heads and a conveyance device. The recording heads each include a plurality of rows of nozzles that eject ink droplets. The conveyance device conveys a sheet of paper, which is a recording medium. The inkjet recording apparatus forms an image on the sheet through each of the recording heads ejecting ink droplets to form dots on the sheet when the sheet is conveyed thereto by the conveyance device.
Typically the recording heads are each positioned at a specific position inside of the inkjet recording apparatus such that the nozzle rows therein are opposite to the conveyance device and such that the nozzle rows are oriented perpendicularly to a sheet conveyance direction. In a situation in which the nozzle rows have a slanted orientation relative to a direction perpendicular to the sheet conveyance direction, the slanting of the nozzle rows causes a shift in positions at which dots are formed (dot formation positions). Consequently, a poorer quality image is formed on the sheet. Therefore, when the recording heads are attached to the inkjet recording apparatus, it is important that positions of the recording heads are precisely adjusted so that the nozzle rows are oriented perpendicularly to the sheet conveyance direction.
PTL1 discloses an example of a printing apparatus in which a shift in dot formation positions is adjusted and printed image quality is improved. The printing apparatus includes a plurality of nozzle units, a sub-carriage, a carriage, and a slant adjusting section. The nozzle units form dots. The sub-carriage can integrally fix the nozzle units. The sub-carriage is attached to the carriage and can slide in a main scanning direction. The slant adjusting section adjusts slanting of the sub-carriage in a yawing direction relative to the main scanning direction. A cam mechanism is used in the slant adjusting section of the printing apparatus.